Has the ecological importance of scale insects
been neglected as a restoration strategy in New Zealand forest ecosystems?

Annette Evans*1, Jacqueline Beggs1, David Towns2

1 University of Auckland2 Department of Conservation

The ecological
importance of scale insects as keystone species has been widely documented both
in New Zealand and worldwide. Although numerous studies have already
examined key interactions within New Zealand honeydew forest ecosystems, large
knowledge gaps still remain surrounding the trophic interactions of endemic
scale insect Coelostomidia zealandica (Coelostomidiidae)
with organisms, especially endemic herpetofauna. Anthropogenic changes have
caused significant reductions in range and abundance of this endemic scale
insect species and its associated fauna. The study site on Korapuki Island,
east of Coromandel peninsula is now one of the sole remaining sites in New
Zealand where C. zealandica and
honeydew exploiters, such as insects and herpetofauna, survive in densities
that are likely to be representative of pre-human conditions. This system provides
an ideal opportunity to evaluate whether the sugar resource is partitioned
between invertebrates and vertebrates. We recorded the abundance and diversity
of faunal visitors to available sugar resources three times daily along a fixed
transect. Large numbers of two species
of endemic gecko were recorded nocturnally feeding on honeydew. Reintroduced
endemic darkling beetles (Mimopeus opaculus)
were seen regularly feeding on honeydew, indicating this sugar resource is
likely to be important in restoring the native fauna. This research will assist
in the development and evaluation of future restoration and management plans
for these ecologically important endemic species. Such research will also
benefit the global entomological community by filling
current global knowledge gaps regarding the strength of trophic interactions;
particularly with insects and herpetofauna; thus creating a more holistic view
of honeydew ecosystems worldwide.